Protectors for electric circuits



A. URANI PROTECTORS FOR ELECTRIC CIRCUITS April s, 1969 Sheet Filed Feb. 27, 1967 April 8, 1969 A. URAN: 3,437,972

` PROTECTORS FOR ELECTRIC CIRCUITS Filed Feb.`27, 1967 sheet of 2 FIG. 7

United States Patent O 3,437,972 PROTECTORS FOR ELECTRIC CIRCUITS Angelo Urani, St. Louis, Mo., assignor to McGraw-Edison Company, Elgin, Ill., a corporation of Delaware Filed Feb. 27, 1967, Ser. No. 618,863

Int. Cl. H01h 85/30, 85/36, 85/46 U.S. Cl. 337-221 28 Claims ABSTRACT OF THE DISCLOSURE This invention relates to improvements in protectors for electric circuits. More particularly, this invention relates to improvements in electric fuses.

It is, therefore, an object of the present invention to provide an improved electric fuse.

It is frequently desirable for an electric fuse to indicate that it has opened the circuit which it is intended to protect. In recognition of that fact, a number of electric fuses have been proposed which had plungers that were normally retracted within the housings of those fuses and that responded to the fusing of the fusible elements of those fuses to extend outwardly from those housings. Where such an electric fuse is mounted in a box or enclosure that is well illuminated, and where that fuse is mounted in a position where it can readily be seen, that fuse can adequately indicate the opening of the circuit protected by it. However, where such an electric fuse is mounted in a box or enclosure that is poorly illuminated, or where that fuse is mounted in a po-sition where it can not readily be seen, that fuse can not adequately indicate the opening of the circuit protected by it. It would be desirable to provide an electric fuse which could indicate that it had opened the circuit which it was protecting, even if that fuse was mounted in a poorly illuminated box or enclosure, and even if that fuse was mounted in a position where it could not readily -be seen. The present invention provides such an electric fuse; and that electric fuse has a plunger which is normally held out of engagement with spaced apart contacts of an indicating circuit and which will move into bridging engagement with those contacts when that fuse opens the circuit which it protects.

Where an indicating circuit is relied upon to indicate that an electric fuse has opened a power-supplying circuit, it is desirable for that indicating circuit to be susceptible of simple and direct testing. Only in that way can one make certain that the indicating circuit will be capable of performing its indicating function when the electric fuse opens the power-supplying circuit. The present invention provides an electric fuse which can coact with an indicating circuit to indicate when that fuse has opened the power-supplying circuit which it protects, and which makes it extremely simple to test that indicating circ-uit. That electric fuse will normally be held, by the terminals of the power-supplying circuit protected by that fuse, adjacent spaced contacts of the indicating circuit; and the mere separation of that electric fuse from those terminals will expose those spaced contacts. Thereupon, that indicating circuit can |be directly and simply tested by using a screw driver, a pair of pliers, a key, or some other metal object to bridge those contacts. It is, therefore, an object of the present invention to provide an electric fuse which can coact with an indicating circuit to indicate when that fuse has opened the power-supplying circuit which it protects, and which makes it extremely simple to test that indicating circuit.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing and accompanying description a preferred embodiment of the present invention is shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the invention and that the invention will be dened by the appended claims.

In the drawing,

FIG. 1 is a perspective view of one preferred embodiment of electric fuse that is made in accordance with the principles and teachings of the present invention,

FIG. 2 is a sectional View, on a larger scale, through the electric fuse of FIG. l, and it is taken along the plane indicated by the line 2 2 in FIG. 1,

FIG. 3 is another sectional view, on the scale of FIG. 2, through the electric fuse of FIG. 1, and it is taken along the plane indicated by the line 3 3 in FIG. 2,

FIG. 4 is a further sectional view, on the scale of FIG. 2, through the electric fuse of FIG. l, and it is taken along the plane indicated 'by the line 4 4 in FIG. 3,

FIG. 5 is an exploded, perspective view of the electric fuse of FIG. 1,

FIG. 6 is a partially broken-away, sectional view of the electric fuse of FIG. l and of the socket for that fuse,

FIG. 7 is a sectional view through the electric fuse and socket of FIG. 6, and it is taken along the plane indicated by the line 7 7 in FIG. 6,

FIG. 8 is a rear elevational view o-f the socket of FIGS. 6 and 7,

FIG. 9 is a sectional View of a portion of the socket of FIGS. 6 and 7 after the fuse of FIG. 1 has been separated from the socket,

FIG. 10 is a front elevational View of a socket which can hold the fuse of FIG. 1 plus three fuses identical to that fuse,

FIG. 11 is a front elevational view of one of the sections of the socket of FIG. 10, and

FIG. 12 is an exploded, perspective view of some of the sections, contacts, and terminals of the socket of F-IG. 10.

Referring to the drawing in detail, the numeral 13 generally denotes the housing `for one preferred embodiment of electric fuse that is made in accordance with the principles and teachings of the present invention. That housing has a section 15 and a section 42; and those sections are preferably formed from a sturdy and tough insulating material. While different insulating materials could be used, the phenolic resins are very usable in making the sections. A small rectangular recess 14 is formed in the section 15, and a complementary recess 44 is formed in the section 42, as shown particularly by FIG. 2. The recess 14 in the section 15 opens into a larger recess 16, and the recess 44 in the section 42 opens into a corresponding recess 46.

`Contiguous recesses 18, 20 and 22 are formed in the section 15 of the housing 13 adjacent one end of that section, as shown particularly by FIGS. 3 and 5. The recess 20` is narower than the recess 18, and the recess 22 is -deeper than either of the recesses 18 and 20. Also, the recess 22 has its axis disposed at right angles to the axes of the recesses 18 and 20. A recess 48 which is complementary to the recess 18, a recess 50 which is complementary to the recess 2i), and a recess 52 which is complementary to the recess 22 are formed in the section 42.

Contiguous recesses 24, 26 and 28 are formed in the section 15 of the housing 13 adjacent the opposite end of that section. The recess 26 is narrower than the recess 24, and the recess 28 is deeper than either of the recesses 24 and 26. Also, the axis of the recess 28 is disposed at right angles to the axes of the recesses 24 and 26. A recess 54 which is complementary to the recess 24, a recess, not shown, which is complementary to the recess 26, and a recess 58 which is complementary to the recess 28 are formed in the section 42 of the housing 13.

The numeral 30 denotes a recess in the section 15 which is coaxial with the recess 16 in that section. The recess 30 has laterally-projecting extensions 31 which communicate with the recesses 22 and 28 in the section 15. The numeral 60 denotes a recess in the section 42 of the housing 13 which is complementary to the recess 30; and the recess 60 has laterally projecting extensions, not shown, which are complementary to the laterally-projecting extensions 31 in the section 15.

Openings 32 and 34 are provided in the section 15 of the housing 13; and the opening 34 is located in a fingerreceiving portion 36 of that section, while the opening 32 is located adjacent the bottom of that section. A shallow recess 38 is formed in the bottom face of the section 15, as shown particularly by FIG. and that recess communicates with the recess 30 in that section. The numerals 62 and 64 denote openings in the section 42 of the housing 13; and the opening 64 is located in a linger-receiving portion 66 of that section, while the opening 62 is located adjacent the bottom of that section. A shallow recess 68 is provided in the bottom face of the section 42, as shown particularly by FIG. 5; and that recess communicates with the recess 60 in that section.

The recesses 18 and 48, the recesses 20 and 50, and the recesses 22 and 52 in the section 15 accommodate, respectively, the lower portion of a terminal 70, the reduced width intermediate portion 72 of that terminal, and the upper portion of that terminal. The lower portion of the upper portion of that terminal will co-act with the sections and 42 to lock that terminal against axial movement within the recesses 18 and 48, 20 and 50, and 22 and 52. The recesses 24 and 54, the recess 26 and its counterpart, not shown, in the section 42, and the recesses 28 and 58 accommodate, respectively, the lower portion of a terminal 74, the reduced width intermediate portion 76 of that terminal, and the upper portion of that terminal. The lower portion and the upper portion of the terminal 74 will coact with the sections 15 and 42 to lock that terminal against axial movement within the recesses 24 and 54, 26 and its counterpart, not shown, and 28 and 58. The depth of each of the recesses 18, 20, 24, 26, 48, 50, and 56 is substantially equal to one-half of the thickness of either of the terminals 70 and 74. Consequently, whenever the sections 15 and 42 of the housing 13 are held in assembled relation, those sections will xedly hold those terminals against appreciable movement relative to that housing.

The numeral 78 denotes a fusible element; and that fusible element is secured to the upper portions of the terminals 70 and 74 by small quantities of solder 80. That fusible element is short-having an effective length of only about three-tenths of an inch in the said preferred embodiment of electric fuse provided by the present invention. Such a short fusible element is desirable; because the length of a short fusible element can not change very much as that fusible element responds to current owing therethrough to become heated. The fusible element 78 will be soldered to the upper portions of the terminals 70 and 74 after those terminals are set, respectively, within the recesses 18, 20, 22, 48, 50 and 52 and 24, 26, 28, 54, and 58 in the sections 15 and 42. That fusible element will be drawn taut as it is soldered to those upper portions of those terminals.

The numeral 82 generally denotes a plunger which is dimensioned to tit Within the recesses 30 and 60 and to 4 extend into the recesses 16 and 46, as shown particularly by FIGS. 3 and 4. That plunger has a generally rectangular socket 84 in the upper end thereof; and that socket is in register with the recesses 14 and 44 in the sections 15 and 42. The plunger 82 also has a recess 86; and that recess extends transversely of the axis of that plunger, and it has a convex wall 87. The recess 86 accommodates the central portion of the fusible element 78; and the convex wall 87 of that recess is intended to bear against a point along the length of that fusible element. An axially directed slot 88 is formed in the plunger 82; and that slot is in register with the openings 32 and 62, respectively, in the sections 15 and 42. A convex face 92 is formed on the lower end of the plunger 82; and a conductive surface 94 overlies that convex face. That surface could be a thin strip of metal cemented or molded to the convex face 92, or it could be a metallized surface on that face.

A helical compression spring 96 has the upper end thereof disposed within the recesses 14 and 44 in the sections 15 and 42, as shown by FIG. 2; and it has the lower end thereof extending into the socket 84 in the plunger 82, as shown particularly by FIGS. 2 and 3. That spring biases the plunger 82 for movement to the left in FIGS. 3 and 6, but the fusible element 78 will normally intercept and hold the convex wall 87 of the recess 86 and thereby prevent such movement, as shown by FIG. 3.

The openings 34 and 64 in the sections 15 and I42 of the housing 13 are in alignment, and they accommodate a rivet 100. Similarly, the openings 3'2 and 62 in those sections are in alignment, and they accommodate a rivet 98. Those rivets will lixedly hold the sections 15 and 42 of the housing 13 in assembled relation.

The numeral 102 generally denotes a socket which is intended to receive the lower portions of the terminals and 74 of the electric fuse of FIG. 1. That socket has asection 104 and a section 132; and those sections preferably are formed from a sturdy and tough insulating material. While different insulating materials could he used, the phenolic resins are very usable in making those sections.

The section 104 has va securing portion 106 with an opening 108 therein; and that securing portion extends outwardly at right angles from the body of the section 104. A recess 110 is formed in the body of the section 104, and that recess opens to the right-hand face of that body. Elongated narrow slots 112 and 114 are formed in the body Vof the section 104, and those slots extend from the inner end of the recess 110 to the lefthand face of the section 104. A slot 118 also is formed in the body of the section 104, and that slot extends from the right-hand face to the left-hand face of that section. A recess 116 is formed in the body of the section 104, and that recess is in register with and communicates with the slot 118. A slot also is formed in the body of the section 104, and that slot extends from the right-hand face to the left-hand face of that body. The slots 112 and 114 are intermediate the slots 118 and 120; and all of those slots are generally parallel to each other. However, the wide faces of the slots 118 and 120 lie in a plane which is at right angles to the planes in which the wide faces of the slots 112 and 114 lie.

Openings 122 and 124 are formed in the body of the section 104, and those openings extend transversely of that body. IRibs 126, 128 and 130 are formed on the left-hand face of the body of the section 104; and those ribs are interposed, respectively, between the left-hand ends of the slots 118 and 112, the slots 112 and 114, and the slots 114 and 120. Those ribs increase the surface distance, between adjacent slots, along the lefthand face of the body of the section 104.

The section 132 has a securing portion 134 which is similar to the securing portion 106 of the section 104.

An opening 136 is provided in the securing portion 134, and that opening corresponds to the opening 108 in the securing portion 106 of the section 104.

The section 132 has a recess 110, shown in FIG. 12, which is identical to the recess 110 in the section 104. The body of the section 132 has slots 140 and 142 which are similar to, and which are in register with, the slots 112 and 114 in the body of the section 104, as shown particularly by FIG. 8. Slots 146 and 148 are formed in the body yof the section 132, and those slots are similar to the slots 118 and 120 in the body of the section 104. However, the slot 14-6 is in register with the slot 120 and the slot 148 is in register with the slot 118, as shown particularly by FIG. 8. A recess 147, shown in FIG. 12, which is similar to the recess 116 is in register with, and communicates with, the slot 1.46.

The body of the section 132 has openings 133 and 135 which are similar to the openings 122 and 124 in the section 104; and those openings are in register with the openings 122 and 124. Ribs 154, 156 and 158 are formed in the body of the section 132, and those ribs are in register with the ribs 126, 128 and 130 on the body of the section 104, as shown particularly by FIG. 8. The ribs 154, 156 and 158 increase the surface distance, between adjacent slots, in the body of the sections 132.

A terminal 170 is set within the space defined by the slots 118 and 148, a terminal 172 is set within the space defined by the slots 120 and 146, a conta-ct 174 is set within the `space defined by the slots 112 and 140, and a Contact 176 is set within the space defined by the slots 114 and 142. The terminals 170 and 172 preferably are identical in configuration; and, as shown particularly by FIG. 9, each of those terminals has an opening adjacent the left-hand end thereof to accommodate a conductor, and has an offset right-hand end with a re-entrant bend. The offset end of the terminal 170 is set within the recess 116 that communi- Cates with the slot 118, and the offset end of the terminal 172 will lodge within the recess 147 in the body of the section 132, as shown by FIG. 12. The angles that are subtended by the re-entrant bends in the righthand ends of the terminals 170 and 172 are larger, when those ends are in their unstressed conditions, than the angles shown by FIG. 9. As a result, those reentrant bends will be under compression whenever the sections 104 and 132 are assembled together and held in intimate engagement.

The contacts 174 and 176 have the inner ends thereof inclined away from each other, as shown particularly by FIG. 6. Those divergent inner ends roughly complement the convex conductive surface 94 on the plunger 82; and hence those divergent inner ends will coact with that convex conductive surface to provide a low resistance connection when the fuse of FIG. 1 opens the circuit which it protects. The left-hand ends of the shanks of the contacts 174 and 176 project outwardly beyond the left-hand ends of the terminals 170 and 172; and those shanks have openings therein to accommodate conductors. In addition, the shanks of the contacts 174 and 17-6 are disposed at right angles to the Shanks 0f the terminals 170 and 172. The extra lengths of the Shanks of the contacts 174 and 176 and the angular dispositions of those shanks are desirable; because they dispose the openings in those Shanks to the left of, and in planes angularly spaced from the planes of, the openings in the left-hand ends of the terminals 170 and 172. As a result, if the electrician who connects the leads of the indicating circuit to the contacts 174 and 176 fails to bend the ends of those leads back into the planes defined by those contacts, or if that electrician fails to bend the leads of the circuit to be protected by the fuse of FIG. l back into the planes defined by the terminals 170 and 172, there will be ample space between the ends of the leads of the indicating circuit and the ends of the leads of the circuit to be protected by the fuse of FIG. l. Consequently, there will be virtually no likelihood of arcs developing between any of those leads.

In assembling the socket 102, the contacts 174 and 176 and the terminals 170 and 172 will be set within the appropriate slots in one or the other of the sections .104 and 132. Thereafter, the other of those sections will be moved into intimate engagement with the section that is holding the contacts 174 and 176 and the terminals 170 and 172. Rivets 160 and 162 will then tbe disposed, respectively, within the openings 122 and 124 and within the corresponding openings in the section 132; and thereafter those rivets will be compressed to permanently hold the sections 104 and 132 of the socket 4102 in assembled relation.

The socket 102 can :be set adjacent an opening 166 in a panel 164, as shown particularly by FIG. 7. Rivets 168 can then be passed through openings in that panel and through the openings 108 and 136 in the securing portions 106 and 134 of the sections 104 and 132. Compression of those rivets will then fixedly hold that socket in assembled relation with that panel.

The contacts 174 and 176 are electrically isolated from the terminals 170 and 172. This is important; because some indicating circuits must be kept wholly separated and isolated from the circuits to be protected by the fuses. The contacts 174 and 176 will be connected to the leads of an indicating circuit; and that circuit will have a lamp, a bell, a buzzer, or the like that will be actuated whenever the convex conductive surface 94 engages the diverging inner ends of those contacts.

The voltage developed across the indicating circuit will usually be considerably smaller than the voltage developed across the circuit to be protected by the electric fuse of FIG. l. The greater spacing between the terminals 170 and 172 prevents flashover and tracking between those terminals; and the lesser voltage across the indicating circuit prevents flashover and tracking between the contacts 174 and 176. The overall result is that the spacing between the confronting edges of the terminals 170 and 172 can be less than four-tenths of an inch-even though the circuit to be protected by the electric fuse of FIG. 1 may have as many as two hundred and lifty volts applied to it, and even though the terminals 170 and 172 and the contacts 174 and 176 open to the same surface of the socket 102.

The electric fuse of FIG. 1 can be set so the terminal 70 thereof can engage the terminal 172 or the terminal 170 of that socket. As a result, precise orientation of that fuse relative to that socket is not necessary. Whether the fuse of FIG. l is set with the terminal 70 thereof in register with the terminal 170 or the terminal 172 of the socket 102, the convex conductive surface 94 on the plunger 82 will be in register with the diverging inner ends of the contacts 174 and 176. As long as the current flowing through the fusible e-lement 78 does not appreciably exceed the rated current of the electric fuse of FIG. 1, that fusible element will remain intact; and it will act to hold the convex conductive surface 94 away from the diverging inner ends of the contacts 174 and 176.

At the time the fusible element 78 is soldered to the upper ends of the terminals 70 and 74, that fusible element will tbe taut and straight. In the absence of play between those terminals and the recesses within the section 15 or 42 in which those terminals are disposed at the time the fusible element 78 is soldered to those terminals, that fusible element will be substantially straight after the sections 15 and 42 have been riveted together and the full force of the spring 96 has been permitted to press the convex wall 87 of the plunger 82 against the central portion of that fusible element. As a result, the curvature of the fusible element 78, indicated by FIGS. 3 and 5, is as great as will be anticipated. Even with that exaggerated curvature, essentially point contact exists between the fusible element 78 and the convex wall 87 on the plunger 82. Such point contact is desirable, because it minimizes the effect which the absorption of heat by that convex wall can have upon the rating of the fuse of FIG. 1. The heat which the convex wall 87 of the plunger 82 will albsorb from the central portion of the fusible element 78 will virtually make certain that the said fusible element will not fuse adjacent the center thereof. Instead, that fusible element will fuse in either or both of the portions of that fusible element which are intermediate the ends thereof and the point where it is engaged by the convex wall 87. Consequently, the fusible element 78 will effectively act as two end-to-end fusible elements of very short length.

The fact that the convex wall 87 of the plunger 82 engages the central portion of the fusible element 78 is additionally desirable, because it tends to keep that fusible element from becoming unduly heated while the fuse of FIG. l is carrying its rated current. Because that fusible element will not become unduly heated at such ti-me, it will not expand appreciably; and hence the plunger 82 wil-l not tbe able to move appreciably to the left in FIGS. 2 and 3 at such time.

Normally the fusible conductor 78 Will hold the plunger 82 in the position shown by FIG. 3, and thus will hold the convex conductive surface 94 on that plunger out of engagement with the contacts 174 and 176. As a result, the indicating circuit to which those contacts are connected will normally be de-energized. Also under normal conditions, current will flow from terminal 170 of the socket 102 via terminal 70, fusible element 78, and terminal74 of the electric fuse to the terminal 172 of that socket, or will flow from the terminal 172 of that socket Via terminal 74, fusible element 78 and terminal 70 of the electric fuse to the terminal .170 of that socket. However, whenever the circuit which is protected by the electric fuse of FIG. l is subjected to a potentially hurtful overload for a predetermined length of time, the fusible element 78 will fuse; and, thereupon, the spring 96 Will force the plunger 82 to the left into the position shown 'by FIG. 6. As that fusible element fuses, the convex wall 87 of the plunger 82 will move directly between the free ends of that fusible element; and hence it will physically interrupt any arc which tends to form as that fusible element fuses.

As the plunger 82 moves into the position shown by FIG. 6, the convex conductive surface 94 thereon will -move into engagement with the diverging inner ends of the contacts 174 and 176. That convex conductive surface will coact with those diverging inner ends to complete the indicating circuit connected to those contacts. The lamp, bell, buzzer, or the like of that indicating circuit will immediately indicate that the fuse of FIG. l has 'been blown. Consequently, the electrician will immediately know which circuit needs to be checked and then refused.

It will be noted that the housing 13 of the fuse of FIG. l and the socket 102 coact to fully enclose and protect the plunger 82 whenever that fuse is assembled with that socket. This is desirable, because it will protect that plunger against any and all injury or damage which might interfere with its movement to bridging position as the fusible element 78 fuses.

It will also be noted that the terminals 170 and 172 are immediately adjacent the opposite ends of the sections 104 and 132 of the socket 102. Consequently, the socket 102 can be made quite small and still be capable of use in some circuits to which appreciably high voltages are applied.

To test the indicating circuit connected to the contacts 174 and 176, it is only necessary to plug a blown fuse into that socket. Alternatively, that circuit can be tested by removing the fuse of FIG. l from the socket 102 and using a screw driver, a pair of pliers, a key, or some other metal object to bridge the diverging inner ends of the contacts 174 and 176.

The convex wall 87 on the plunger 82 has a mold smoot surface that is free of Hash or lin; and that Wall is smoothly rounded. As a result, that convex wall will not tend to apply sharp, concentrated forces to the fusible element 78 which could unduly fatigue that fusible element. The convex Wall 87 will act to bend the inwardly extending free ends of the fusible element 78 outwardly when that fusible element fuses; and hence that convex wall will facilitate the movement of the plunger 92 into position between those inwardly extending free ends. Such movement is important in enabling the convex conductive surface 94 on the convex face 92 of that plunger to move into bridging engagement with the diverging upper ends of the contacts 174 and 176; and such movement also is important in enabling that plunger to help extinguish any arc that forms as the fusible element 78 fuses. The recesses 31 in the section 15, and the corres ponding recesses in the section 42, permit the inwardly extending free ends of Ithe blown fusible element 78 to bevmoved away from each other as the plunger 82 moves to the left in FIG. 3.

FIG. l0 discloses a socket which includes the sections 104 and 132 plus three intermediate sections 180, 182 and 183. All of those intermediate sections are identical; and each of those intermediate sections has a number of slots and recesses in the opposite surfaces thereof. Specifically, each of those intermediate sections has a slot 146, a slot 142, a slot 140, a slot 148, a recess 147, and a recess 110 in the left-hand surface thereof. Also, each of those intermediate sections has a slot 120, a slot 114, a slot 112, a slot 118, a recess 116, and a recess 110 in the right-hand surface thereof. Further, each of lthose intermediate sections has ribs 192, 190 and 1-88 thereon that are similar to and that can be aligned with the ribs 126 and 154, 128 and 156, and 130 and 158, respectively, on the sections 104 and 132. Moreover, each of those intermediate sections has openings 196 and 198 therein which are similar to and that can be aligned with the openings 124 and 122, respectively, in the section 104.

The recess 147 in the intermediate section 180 can be set in register with, and in confronting relation to, the slot in the section 104; and the recess 116 in the section 104 will then confront and be in register with the slot 148 in the intermediate section 180. The slots 146, 142, and 14-8 in the left-hand surface of the intermediate section 180 will confront and be in register with the recesses 120, 114, 112 and 118, respectively, of the section 104. 'Ihe two sets of slots will coact to accommodate terminal 172, contacts 176 and 174, and terminal 170. The slots and recesses in the right-hand surface of the intermediate section 180 will coact with the slots and recesses in the left-hand surface of the intermediate section 182 to support further terminals 170 and 172 and further contacts 174 and 176. The slots and recesses in the right-hand surface of the intermediate section 182 will coact with the slots and recesses in the left-hand surface of the intermediate section 183 to support still further terminals and 172 and still further contacts 174 and 176. The slots and recesses in the right-hand sur-face of the intermediate section 183 will coact with the slots and recesses in the left-hand surface of the section 132 to support yet another set of terminals 170 and 172 and contacts 17 4 and 176.

Elongated bolts 184 and 186 extend through the aligned openings in the sections 104 and 132 and through the aligned openings in the intermediate sections 180, 182 and 183; and those bolts will coact with nuts to fxedly hold the components of the socket of FIG. 10 in assembled relation. That socket can accommodate four closely spaced fuses, and it makes it possible for those fuses to protect four separate circuits. Also, that socket makes it possible for any one of four indicating circuits to provide an indication when the fuse associated with that indicating circuit blows. It would be possible to assemble the sections 104 and 132 with more or fewer intermediate sections; and, consequently, the present invention makes it possible to dispose Iany desired number of electric fuses in closely spaced proximity and to enable those fuses to protect a corresponding number of circuits and to actuate a corresponding number `of indicating circuits.

It will be noted that the terminals 170 and 172 do not have to be staked, riveted, bolted or otherwise fastened to the section 104, the section 132 or any of the intermediate sections. Similarly, it will be noted that the contacts 174 and 176 do not have to be staked, riveted, bolted or otherwise fastened to the sections 104 or 132 or to any of the intermediate sections. Instead, the mere assembling of the sections 104 and 132I and the intermediate sections in intimate engagement with each other will precisely and xedly position those 4terminals and contacts and hold them in assembled relation with the rest of the socket.

It will be noted that the plunger `82 is confined and guided for rectilinear movement by the walls of the recesses 16 and 30 in the section 15 and by the walls of the corresponding recesses in the section 42 of the fuse housing 13; and that the fusible element 78 is disposed transversely of the direction of movement of that plunger. This is important; -because it minimizes the effect which variations in the effective length of that fusible element could have upon the position of that plunger. Specifically, if the fusible element 78 was arranged so it was parallel to, rather than transverse of, the direction of movement of the plunger 82, any variations in the effective length of that fusible element-due to manufacturing tolerances in the -dimensioning of that fusible element, to manufacturing tolerances in the soldering of that fusible element, or to the heating of that fusible element would effect corresponding variations in the position of the plunger 82. However, because the fusible element 78 is actually transverse of, rather than parallel to, the direction of movement of the plunger 82, any variations in the effective length of that fusible element will not effect corresponding `variations in the position of that plunger-the variations in the position of that plunger merely being the product of one-half the variations in the length of that fusible element multiplied by the sine of the angle of deflection of that fusible element. As a result, the position of the plunger 82 is largely independent of any variations in the length of the fusible element 78.

While the walls of the recesses 16 and 30 in the section 15 will coact with the walls of the corresponding recesses in the section 42 to confine and guide the plunger 82 for rectilinear movement, there will be an appreciable amount of play 'I'hat play is important; because it keeps that plunger from sticking in position within the fuse housing 13, and because it permits the convex conductive surface 94 on the plunger 82 to center itself as it engages the diverging inner ends of the contacts 174 and 176 of the fuse socket. The resulting intimate engagement between that :convex conductive surface and those contacts will provide a desirably low resistance bridging of those contacts.

Whereas the drawing and accompanying description have shown and described a preferred embodiment of the present invention, it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I claim is:

1. An electric fuse and a socket therefor which comprise:

a housing,

a plunger carried by, but being movable relative to, said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried by said housing,

between that plunger and those walls.

a fusible element electrically connected to said terminals,

said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electrically conducting relation with, said spaced terminals carried by said support,

said spaced terminals carried by said housing normally coacting with said spaced terminals carried by sai-d support to hold said conductive surface on said plunger in register with said spaced contacts carried by said support,

whereby fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts :carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit.

2. An electric fuse 4and a socket therefor as claimed in claim 1 wherein said housing has guiding .and confining surfaces that guide and confine said plunger for rectilinear movement and wherein said conductive surface is on one end of said plunger.

3. An electric fuse and a socket therefor as claimed in claim 1 wherein said housing has guiding :and confining surfaces that guide and confine said plunger for rectilinear movement and wherein said fusible element is disposed transversely of the direction of movement of said plunger.

4. An electric fuse and a socket therefor which comprises:

a housing,

a plunger carried by, but being movable relative to, said housing,

a conductive surfaceon said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried -by said housing,

a fusible element electrically connected to said terminals,

Said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electrically-conducting relation with, said spaced terminals carried by said support,

said spaced terminals :carried by said housing normally coacting with said spaced terminals carried by said support to hold said conductive surface on said plunger in register with said spaced contacts carried by said support,

whereby fusing of said'fusible element will permit said spring to move said plunger outwardly of said housing until said conductive -surface on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

said fusible element being disposed transversely of the direction of movement of said plunger, whereby any variations in the position of said plunger, due to variations in the effective length of said fusible element, will be smaller than the product of said variations in the effective length of said fusible element multiplie-d by the sine of the angle of deflection of said fusible element.

5. An electric fuse and a socket therefor as claimed in claim 1 wherein said portion of said plunger is a Wall of a recess in said plunger, said fusible element extending through said recess and extending beyond said re'- cess to engage said terminals carried by said housing.

6. An electric fuse and a socket therefor as claimed in claim 1 wherein said portion of said plunger is a convex surface, said convex surface coacting with said fusible element to limit the engagement between said plunger and said fusible element essentially to point contact.

7. An electric fuse and a socket therefor which comprises:

a housing,

a plunger carried by, but being movable relative to,

said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried by said housing,

a fusible element electrically connected to said terminals,

said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being diposable in register with, and normally being held in electrically-conducting relation with, said spaced terminals carried by said support,

said spaced terminals carried by said housing normally coacting with said spaced terminals carried by said support to hold said conductive surface on said plunger in register with said spaced Icontacts carried by said support,

whereby fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

' said portion of said plunger being a wall of a recess in said plunger,

said fusible element extending through said recess and extending beyond said recess to engage said terminals carried by said housing,

said wall of said recess being convex to limit the engagement between said plunger and said fusible element essentially to point contact.

8. An electric fuse and socket therefor which comprises:

a housing,

a plunger carried by, but being movable relative to, said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried by said housing,

a fusible element electrically connected to said terminals,

said fusible element normally being disposed .in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in -register with, and normally being held in electrically-conducting relation with, said spaced terminals carried by said support,

said spaced terminals carried by said housing normally coacting with said spaced terminals carried by said :support to hold said conductive surface on said plunger in register with said spaced contacts carried by said support,

whereby fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

said housing being immediately adjacent said support whenever said terminals carried by said housing are held in electrically conducting relation with said terminals carried by said support,

said Ihousing and said support coacting, whenever said housing is immediately adjacent said support, to substantially fully enclose and protect said plunger.

9. An electric fuse and a socket therefor which comprises:

a spring that -biases said plunger for movement outv wardly of said housing,

`spaced terminals carried by said housing,

a fusible element electrically connected to said termina-ls,

said 4fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electrically conducting relation with, said spaced terminals carried by said support,

Said spaced terminals carried by said housing normally coacting with said spaced terminals carried by said support to hold said conductive surface on said lplunger in register with said spaced contacts carried by said support,

whereby fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

said housing holding said conductive surface on said plunger a short distance away from said contacts carried by said support whenever said terminals carried by said housing are held in electrically conducting relation with said terminals carried by said support and said housing is disposed immediately adjacent said support and said fusible element is intact.

10. An electric fuse and a socket therefor as claimed in claim 1 wherein those portions of said contacts carried by said support that confront said conductive surface on said plunger diverge from each other.

11. An electric fuse and a socket therefor as claimed in claim 1 wherein said contacts carried by said support can be exposed, for purposes of testing the indicating circuit to which said contacts are connectable, by the mere separation of said housing from said support.

12. An electric fuse and a socket therefor which comprises:

a housing,

a plunger carried by, but being movable relative to,

said housing,

a conductive surface on said plunger,

a spring that biasescsaid plunger from movement outwardly of said housing,

spaced terminals carried lby said housing,

a fusible element electrically connected to said terminals,

said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried -by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electrically conducting relation with, said spaced terminals carried `by said support,

said spaced terminals carried by said housing normally coacting with said spaced terminals carried by said support to hold said conductive surface on said plunger in register with said spaced contacts carried by said support,

whereby fusing of said fusible element will permit said spring to move saidplunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts carried -by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said 'spaced contacts carried by said support being connectable to an indicating circuit,

said terminals carried by said support being disposed adjacent the ends of said support and said contacts prises:

a housing,

a plunger carried by, but being movable relative to,

said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

lspaced terminals carried by said housing,

a fusible element electrically connected to said terminals,

said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electrically conducting relation with, said spaced terminals carried 'by said support,

said spaced terminals carried by said housing normally coasting with said spaced terminals carried by said support to hold said conductive surface on said plunger in register with said spaced contacts carried by said support,

whereby `fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

said terminals carried by said support being angularly displaced from said contacts carried by said support, whereby leads of said circuit to be protected by said fusible element that are connected to said terminals carried by said support will tend to be spaced from leads of said indicating circuit that are connected to said contacts carried by said support.

14. An electric fuse and a socket therefor which comprises:

a housing,

a plunger carried by, but being movable relative to said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried by said housing,

a fusible element electrically connected to said terminals,

said fusible element normaly being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardy of said housing,

said fusible element responding to a predetermined electrical overloadto fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electrically conducting relation with, said spaced terminals carried by said support,

said spaced terminals carried by said housing normally coacting with said spaced terminals carried by said support to hold said conductive surface on said plunger in register with said spaced contacts carrier by said support,

whereby fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

said terminals carried by said support having lengths different than the lengths of said contacts carried by said support, whereby leads of said circuit to be protected by said fusible element that are connected to said terminals carried by said support will tend to be spaced from leads of said indicating circuit that are connected to said contacts carried by said support.

15. An electric fuse and a socket therefor as claimed in claim 1 wherein said housing has recesses adjacent said fusible element into which portions of said fusible element can be moved by said plunger as said plunger is moved by said spring after said fusible element fuses.

16. An electric fuse and a socket therefor which comprises:

ahousing,

a plunger carried by, but being movable relative to,

said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried by said housing,

a fusible element electrically connected to said terlrninals.

said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electricallyconducting relation with, said spaced terminals carried by said support,

said spaced terminals carried by said housing normally coacting with said spaced terminals carried by said support to hold said conductive surface on said plunger in register with said spaced contacts carried by said support,

whereby fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive surface on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

said housing having recesses adjacent said fusible element into which portions of said fusible element can be moved by said plunger as said plunger is trnoved by said spring after said fusible element fuses,

said portion of said plunger being convex and thereby facilitating the lmovement of said portions of said fusible element into said recesses in said housing as said plunger is moved by said spring after said fusible element fuses.

17. An electric fuse and a socket therefor as claimed in claim 1 wherein said housing has guiding and confining surfaces that guide and confine said plunger, said plunger being dimensioned relative to said guiding and confining surfaces to provide appreciable play between itself and said guiding and confining surfaces, said play enabling said plunger to center itself as said conductive surface thereon moves into engagement with said contacts carried by said support.

i8. An electric fuse and a socket there-for which comprises:

a housing,

a plunger carried by, but being movable relative to,

said housing,

a conductive surface on said plunger,

ra spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried by said housing,

a fusible element electrically connected to said terminals,

said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent springinduced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

a support,

spaced terminals carried by said support, and

spaced contacts carried by said support,

said spaced terminals carried by said housing being disposable in register with, and normally being held in electrically conducting relation lwith, said spaced terminals carried by said support,

said spaced terminals carried by said housing normally coacting with said spaced terminals carried by said support to hold said conductive surface on said plunger in register with said spaced contacts carried by said support,

whereby fusing of said fusible element will permit said spring to move said plunger outwardly of said housing until said conductive sur-face on said plunger engages, and makes electrical connections with, said spaced contacts carried by said support,

said spaced terminals carried by said support being connectable to a circuit to be protected by said fusible element,

said spaced contacts carried by said support being connectable to an indicating circuit,

said housing having guiding and confining surfaces that guide and confine said plunger,

said plunger being dimensioned relative to said guiding and confining surfaces to provide appreciable play between itself and said guiding and confining surfaces, said play enabling said plunger to center itself as said conductive surface thereon moves into engagement with said contacts carried by said support,

said conductive surface on said plunger being convex to facilitate said centering of said plunger as said conductive surface thereon moves into engagement with said contacts carried by said support.

19. An electric fuse that comprises:

a housing,

a plunger carried by, but being movable relative to,

said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried by said housing,

a fusible element electrically connected to said terminals,

said fusible element normally being disposed in the path of movement of a portion of said plunger to normal- 1y prevent spring-induced movement of said plunger outwardly of said housing,

said -fusible element responding to a predetermined electrical overload to fuse and thereby permit said spring to move said plunger outwardly of said housing,

said housing being disposable adjacent a socket, for said electric fuse, to dispose said conductive surface on said plunger in register with spaced contacts of an indicating circuit carried by said socket,

whereby movement of said plunger outwardly of said housing, when said fusible element responds to a predetermined electrical overload to fuse, will enable said conductive surface on said plunger to engage said spaced contacts,

said portion of said plunger being a convex surface,

said convex surface coacting with said fusible element to limit the engagement |between said plunger and said -fusible element essentially to point contact.

20. An electric fuse that comprises:

a housing,

a plunger carried by, but being movable relative to,

said housing,

a conductive surface on said plunger,

a spring that biases said plunger for movement outwardly of said housing,

spaced terminals carried `by said housing,

a fusible element electrically connected -to said terminals,

said fusible element normally being disposed in the path of movement of a portion of said plunger to normally prevent spring-induced movement of said plunger outwardly of said housing,

said fusible element responding to a predetermined electrical overload -to fuse and thereby permit said spring to move said plunger outwardly of said housms,

said housing being disposable adjacent a socket, for said electric fuse, to dispose said conductive surface on said plunger in register with spaced contacts of an indicating circuit carried by said socket,

whereby movement of said plunger outwardly of said housing, when said fusible element responds to a predetermined electrical overload to fuse, will enable said conductive surface on said plunger to engage said spaced contacts,

said portion of said plunger being a wall of a recess in said plunger,

said fusible element extending through said recess and extending 'beyond said recess to engage said terminals carried by said housing,

said wall of said recess being convex to limit the engagement between said plunger and said fusible element essentially to point contact.

21. A socket for an electric fuse which comprises:

a section of insulating material that has a plurality of spaced slots in one surface thereof,

a second section of insulating material that has a plurality of spaced slots in one surface thereof which confronts said one surface of the -iirst said section,

one of said slots in said one surface of the first said section and one of said slots in said one surface of said second section being in register with each other and accommodatingfa terminal which can be engaged by a terminal of an electric fuse,

a second of said slots in said one surface of the first said section and a second of said slots in said one surface of said second section being in register with each other and accommodating a contact which can be engaged by a conductive surface of said electric fuse,

a third of said slots in said one surface of the first said section and a third of said slots in said one surface of said second section being in register with each other and accommodating a second contact which can be engaged by said conductive surface of said electric fuse,

a fourth of said slots in said one surface of the iirst said section and a fourth of said slots in said one surface of said second section being in register with each other and accommodating a second terminal which can be engaged by a second terminal of said electric fuse,

said one slots of said sections having depths less than the thickness of the iirst said terminal and coacting with each other to mechanically hold said terminal in assembled relation with said socket whenever said sections are held in assembled relation,

said second slots of said sections having depths less than the thickness of the first said contact and coacting with each other to mechanically hold said contact in assembled relation with said socket whenever said sections are held in assembled relation,

said third slots of said sections having depths less than the thickness of said second contact and coacting with each other to mechanically hold said second contact in assembled relation with said socket whenever said sections are held in assembled relation,

said fourth slots of said sections having depths less than the thickness of said second terminal and coacting with each other to mechanically hold said second terminal in assembled relation with said socket whenever said sections are held in assembled relation, and fasteners holding said sections in assembled relation.

22. A socket for an electric fuse which comprises:

a section of insulating material that has a plurality of spaced slots in one surface thereof,

a second section of insulating material that has a plurality of spaced slots in one surface thereof which confronts said one surface of the first said section,

one of said slots in said one surface of the first said section and one of said slots in said one surface of said second section being in register with each other and accommodating a terminal which can be engaged by a terminal of an electric fuse,

a second of said slots in said one surface of the first said section and a second of said slots in said one surface of said second section being in register with each other and accommodating a contact which can be engaged by a conductive surface of said electric fuse,

a third of said slots in said one surface of the first said section and a third of said slots in said one surface of said second section being in register with each other and accommodating a second contact which can be engaged by said conductive surface of said electric fuse,

a fourth of said slots in said one surface of the first said section and a fourth of said slots in said one surface of said second section being in register with each other and accommodating a second terminal which can be engaged by a second terminal of said electric fuse,

said one slots of said sections having depths less than the thickness of the first said terminal and coacting with each other to mechanically hold said terminal in assembled relation with said socket whenever said sections are held in assembled relation,

said second slots of said sections having depths less than the thickness of the first said contact and coacting with each other to mechanically hold said contact in assembled relation with said socket whenever said sections are held in assembled relation,

said third slots of said sections having depths less than the thickness of said second contact and coacting with each other to mechanically hold said second contact in assembled relation with said socket whenever said sections are held in assembled relation,

said fourth slots of said sections having depths less than the thickness of said second terminal and coact ing with each other to mechanically hold said second terminal in assembled relation with said socket when ever said sections are held in assembled relation, and fasteners holding said sections in assembled relation,

one of said sections having a recess adjacent to, and

communicating with, said one slot therein to accommodate a bent end of said terminal and said one slot of the other of said sections being free of a corresponding recess, and

said other of said sections having a recess adjacent to, and communicating with, said fourth slot therein to accommodate a bent end of said second terminal and said fourth slot of said one of said sections being free of a corresponding recess.

23. A socket for an electric fuse as claimed in claim 2-1 wherein a rib is interposed between said one and said second slots of said one section, a second rib is interposed between said second and said third slots of said one section, a third rib is interposed between said third and said fourth slots of said one section, a fourth rib is interposed between said one and said second slots of said second section, a fifth rib is interposed between said second and said third slots of said second section, and a sixth rib is interposed between said third and said fourth slots of said second section.

24. A socket for an electric fuse as claimed in claim 21 wherein a rib is interposed between said one and said second slots of said one section, a second rib is interposed between said second and said third slots of said one section, a third rib is interposed between said third and said fourth slots of said one section, a fourth rib is interposed Ibetween said one and said second slots of saidsecond ection, a fifth rib is interposed between said second and said third slots of said second section, and a sixth rib is interposed between said third and said fourth slots of said second section, said first and said fourth ribs being in register, said second and said fifth ribs being in register, and said third and said sixth ribs being in register.

25. A socket for an electric fuse which comprises:

a section of insulating material that has a plurality of spaced slots in one surface thereof,

a second section of insulating material that has a plurality of spaced slots in one surface thereof which confronts said one surface of the first said section,

one of said slots in said one surface of the first said section and one of said slots in said one surface of said second section being in register with each other and accommodating a terminal which canbe engaged by a terminal of an electric fuse,

a second of said slots in said one surface f the first said section and a second of said slots in said one surface of said second section being in register with each other and accommodating a Contact which can be engaged by a conductive surface of said electric fuse,

a third of said slots in said one surface of the first said section and a third of said slots in said one surface of said second section being in register with each other and accommodating a second contact which can -be engaged by said conductive surface of said electric fuse,

a fourth of said slots in said one surface of the first said section and a fourth of said slots in said one surface of said second section being in register with each other and accommodating a second terminal which can be engaged by a second terminal of said electric fuse,

said one slots of said sections having depths less than the thickness of the first said terminal and coacting with each other to mechanically hold said terminal in assembled relation with said socket whenever said sections are held in assembled relation,

said second slots of said sections having depths less than the thickness of the first said contact and coacting with each other to mechanically hold said contact in assembled relation with said socket whenever said sections are heldin assembled relation.

said third slots of said sections having depths less than the thickness of said second contact and coacting with each other to mechanically hold said second contact in assembled relation with said socket whenever said sections are held in assembled relation,

said fourth slots of said sections having depths less than the thickness of said second terminal and coacting with each other to mechanically hold said second terminal in assembled relation with said socket whenever said sections are held in assembled relation, and

fasteners holding said sections in assembled relation,

said one and said fourth slots in said one surfaces of said sections being oppositely disposed of said second and said third slots in said one surfaces of said sections, whereby greater spacing is provided between said one and said fourth slots than between said second and said third slots.

26. A socket for an electric fuse which comprises:

a section of insulating material that has a plurality of spaced slots in one surface thereof,

a second section of insulating material that has a plurality of spaced slots in one surface thereof which confronts said one surface of the first said section,

one of said slots in said one surface of the first said section and one of said slots in said one surface of said second section being in register with each other and accommodating a terminal which can be engaged by a terminal of an electric fuse,

a second of said slots in said one surface of the first said section and a second of said slots in said one surface of said second section being in register with each other and accommodating a contact which can be engaged by a conductive surface of said electric fuse,

a third of said slots in said one surface of the first said section and a third of said slots in said one surface of said second section being in register with each other and accommodating a second contact which can be engaged by said conductive surface of said electric fuse,

a fourth of said slots in said one surface of the first said section and a fourth of said slots in said one surface of said second section being in register with each other and accommodating a second terminal which can be engaged by a second terminal of said electric fuse,

said one slots of said sections having depths less than the thickness of the first said terminal and coacting with each other to mechanically hold said terminal in assembled relation with said socket whenever said sections are held in assembled relation,

said second slots of said sections having depths less than the thickness of the first said contact and coacting with each other to mechanically hold said contact in assembled relation with said socket whenever said sections are held in assembled relation,

said third slots of said sections having depths less than the thickness of said second contact and coating with each other to mechanically hold said second contact in assembled relation with said socket whenever said sections are heldin assembled relation,

said fourth slots of said sections having depths less than the thickness of said second terminal and coacting with each other to mechanically hold said second terminal in assembled relation with said socket whenever said sections are held in assembled relation, and

fasteners holding said sections in assembled relation,

the first said and said second terminals having projecting Shanks that are dissimilar in length from the projecting Shanks of said contacts to minimize the likelihood of contact between leads secured to said projecting shanks of said terminals and leads secured to said projecting Shanks of said contacts.

27. A socket for an electric fuse which comprises:

a section of insulating material that has a plurality of spaced slots in one surface thereof,

a second section of insulating material that has a plurality of spaced slots in one surface thereof which confronts said one surface of the first said section,

one of said slots in said one surface of the first said section and one of said slots in said one surface of said second section -being in register with each other and accommodating a terminal which can be engaged by a terminal of an electric fuse,

a second of said slots in said one surface of the first said section and a second of said slots in said one surface of said second section being in register with each other and accommodating a Contact which can be engaged by a conductive surface of Vsaid electric fuse,

a third of said Slots in said one surface of the first said section and a third of said slots in said one surface of said second section being in register with each other and accommodating a second contact which can be engaged by said conductive surface of said electric fuse,

a fourth of said slots in said one surface of the first said section and a fourth of said slots in said one surface of said second section being in register with each other and accommodating a second terminal which can be engaged by a second terminal of said electric fuse,

said one slots of said sections having depths less than the thickness of the first said terminal and coacting with each other to mechanically hold said terminal in assembled relation with Said socket Iwhenever said sections are held in assembled relation,

Said second slots of said sections having depths less than the thickness of the first said Contact and coacting with each other to mechanically hold Said contact in assembled relation with said socket whenever Said sections are held in assembled relation,

said third Slots of said sections having depths less than the thickness of said second contact and coacting with each other to mechanically hold said second contact in assembled relation with said socket whenever said sections are held in assembled relation,

said fourth slots of said sections having depths less than the thickness of said second terminal and coacting with each other to mechanically hold said second terminal in assembled relation with said socket whenever Said sections are held in assembled relation, and

fasteners holding said sections in assembled relation,

the first Said and said second terminals having projecting Shanks that are angularly displaced from the projecting Shanks of said contacts to minimize the likelihood of contact between leads secured to said pro- 'jecting shanks of said terminals and leads secured to said projecting Shanks of said contacts.

28. A socket for an electric fuse which comprises:

a section of insulating material that has a plurality of space slots in one surface thereof,

a second section of insulating material that has a plurality of spaced Slots in one surface thereof which confronts said one surface of the first said section,

one of said slots in said one surface of the first said section and one of said slots in said one surface of said second section being in register with each other and accommodating a terminal which can be engaged by a terminal of .an electric fuse,

a second of said slots in said one surface of the first said Section and a second of said slots in said one surface of said second section being in register with each other and accommodating a contact which can be engaged by a conductive Surface of said electric fuse,

a third of Said Slots in said one surface of the first said section and a third of said slots in said one surface of said second Section being in register with each other and accommodating a second contact which can be engaged by said conductive surface of said electric fuse,

a fourth of Said slots in said one surface of the first said Section and a fourth of said slots in said one Surface of said second section being in register with each ofher and accommodating a second terminal which can be engaged by a Second terminal of said electric fuse,

said one slots of said Sections having depths less than the thickness of the first said terminal and coacting with each other to mechanically hold said terminal in assembled relation with said socket whenever said sections are heldin assembled relation,

Said second slots of said sections having depths less than the thickness of the first Said contact and coacting with each other to mechanically hold said contact in assembled relation with said socket whenever said sections are held in assembled relation,

said third slots of Said sections having depths less than the thickness of said second contact and coacting with each other to mechanically hold said second contact in assembled relation with said Socket whenever Said sections are held in assembled relation,

said fourth slots of said sections having depths less than the thickness of said second terminal and coacting with each other to mechanically hold said second terminal in assembled relation with Said socket whenever said Sections are held in assembled relation, and

fasteners holding said sections in assembled relation,

said second section being an intermediate section and having a plurality of slots in a second surface thereon, and

a third section having a plurality of slots in a surface thereon which confronts said second surface on said second section,

said slots in said second surface on said second section coacting with said slots in said surface on said third section to hold a third terminal, a third contact, a fourth contact, and a fourth terminal whenever said sections are heldin assembled relation.

References Cited UNITED STATES PATENTS 1,848,152 3/1932 Bieger 337-31 2,530,228 11/1950 Cihlar et al. 337-417 2,581,308 l/1952 Smith 337-9 2,809,256 8/ 1957 Bullinger 337-267 3,238,334 3/1966 Lopasic et al. 3-37-195 3,319,027 5/ 1967 Hitchcock 337-276 590,750 9/ 1897 Cartwright 337-278 BERNARD A. GILHEANY, Primary Examiner. HIRAM B. GILSON, Assistant Examiner.

U.S. Cl. X.R. 

